U.S. patent application number 14/578002 was filed with the patent office on 2015-07-02 for combinatorial chemistries for matching multiple batteries.
The applicant listed for this patent is Johnson Controls Technology Company. Invention is credited to Brian C. Sisk, Thomas M. Watson, Zhenli Zhang.
Application Number | 20150188188 14/578002 |
Document ID | / |
Family ID | 53482912 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150188188 |
Kind Code |
A1 |
Zhang; Zhenli ; et
al. |
July 2, 2015 |
COMBINATORIAL CHEMISTRIES FOR MATCHING MULTIPLE BATTERIES
Abstract
A micro-hybrid battery system includes a lithium ion battery
module configured to be coupled to an electrical load. The lithium
ion battery module includes a housing. The lithium ion battery
module also includes a first lithium ion battery cell disposed in
the housing and having a first active material chemistry including
a first cathode active material and a first anode active material.
The lithium ion battery module also includes a second lithium ion
battery cell electrically connected to the first lithium ion
battery cell and disposed in the housing. The second lithium ion
battery cell has a second active material chemistry including a
second cathode active material and a second anode active material.
The first and second active material chemistries are different such
that the first and second lithium ion battery cells have different
open circuit voltages.
Inventors: |
Zhang; Zhenli; (Glendale,
WI) ; Sisk; Brian C.; (Mequon, WI) ; Watson;
Thomas M.; (Milwaukee, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnson Controls Technology Company |
Holland |
MI |
US |
|
|
Family ID: |
53482912 |
Appl. No.: |
14/578002 |
Filed: |
December 19, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61923118 |
Jan 2, 2014 |
|
|
|
Current U.S.
Class: |
429/9 ;
29/623.1 |
Current CPC
Class: |
Y10T 29/49108 20150115;
H01M 10/058 20130101; H01M 10/0525 20130101; Y02T 10/70 20130101;
Y02P 70/50 20151101; B60L 50/60 20190201; H01M 2/1077 20130101;
H01M 2220/20 20130101; Y02T 10/7016 20130101; H01M 16/00 20130101;
Y02T 10/7011 20130101; B60L 58/20 20190201; H01M 4/131 20130101;
H01M 10/06 20130101; Y02T 10/7061 20130101; Y02T 10/7066 20130101;
B60L 2240/547 20130101; H01M 4/587 20130101; H01M 4/485 20130101;
Y02E 60/10 20130101; Y02E 60/126 20130101; B60L 58/22 20190201;
H01M 4/133 20130101; B60L 58/19 20190201; Y02E 60/122 20130101;
H01M 10/4264 20130101; Y02P 70/54 20151101; B60L 58/26 20190201;
B60L 2240/545 20130101; B60L 2240/549 20130101; H01M 4/525
20130101; Y02T 10/7044 20130101; B60L 58/13 20190201; B60L 50/66
20190201 |
International
Class: |
H01M 10/0525 20060101
H01M010/0525; H01M 10/058 20060101 H01M010/058; H01M 10/42 20060101
H01M010/42; H01M 4/131 20060101 H01M004/131; H01M 4/133 20060101
H01M004/133; H01M 2/10 20060101 H01M002/10; H01M 10/06 20060101
H01M010/06 |
Claims
1. A micro-hybrid battery system, comprising: a lithium ion battery
module configured to be coupled to an electrical load, wherein the
lithium ion battery module comprises: a housing; a first lithium
ion battery cell disposed in the housing and having a first active
material chemistry comprising a first cathode active material and a
first anode active material; and a second lithium ion battery cell
electrically connected to the first lithium ion battery cell and
disposed in the housing, wherein the second lithium ion battery
cell has a second active material chemistry comprising a second
cathode active material and a second anode active material, wherein
the first and second active material chemistries are different such
that the first and second lithium ion battery cells have different
open circuit voltages.
2. The micro-hybrid battery system of claim 1, comprising an energy
storage unit electrically coupled in parallel to the lithium ion
battery module, and wherein the energy storage unit and the lithium
ion battery are voltage matched.
3. The micro-hybrid battery system of claim 2, wherein the lithium
ion battery module comprises a plurality of lithium ion battery
cells having the first and second lithium ion battery cells, and
the plurality of lithium ion battery cells is configured such that
the lithium ion battery module has a voltage profile of voltage as
a function of state of charge (SOC) that overlaps an operating
window of the micro-hybrid battery system, the overlap occurring
within a SOC range of the voltage profile in which the lithium ion
battery module is intended to operate within the micro-hybrid
battery system, wherein the operating window of the micro-hybrid
battery system depends at least on the energy storage unit.
4. The micro-hybrid battery system of claim 3, wherein the
plurality of lithium ion battery cells is configured such that the
voltage profile of the lithium ion battery module overlaps the
operating window of the micro-hybrid battery system within a lower
half of the SOC range.
5. The micro-hybrid battery system of claim 3, wherein the
plurality of lithium ion battery cells is configured such that the
voltage profile of the lithium ion battery module overlaps the
operating window of the micro-hybrid battery system within an upper
half of the SOC range.
6. The micro-hybrid battery system of claim 2, wherein the lithium
ion battery module comprises a plurality of lithium ion battery
cells having the first and second lithium ion battery cells, and
the plurality of lithium ion battery cells is configured such that
the lithium ion battery module has a voltage profile of voltage as
a function of state of charge (SOC) that overlaps a voltage window
of the energy storage unit, the overlap occurring within a first
SOC range of the voltage profile in which the lithium ion battery
module is intended to operate within the micro-hybrid battery
system, wherein the voltage window of the energy storage unit
corresponds to a second SOC range in which the energy storage unit
is intended to operate within the micro-hybrid battery system.
7. The micro-hybrid battery system of claim 6, wherein the
plurality of lithium ion battery cells is configured such that the
voltage profile of the lithium ion battery module overlaps the
voltage window of the energy storage unit within a lower half of
the SOC range.
8. The micro-hybrid battery system of claim 6, wherein the
plurality of lithium ion battery cells is configured such that the
voltage profile of the lithium ion battery module overlaps the
voltage window of the energy storage unit within an upper half of
the SOC range.
9. The micro-hybrid battery system of claim 2, wherein the energy
storage unit is a 12 V automotive lead acid battery and the lithium
ion battery module is a micro-hybrid lithium ion battery module
configured to capture electrical energy from a regenerative braking
system of an xEV.
10. The micro-hybrid battery system of claim 1, wherein the first
cathode active material and the second cathode active material are
the same, and the first anode active material and the second anode
active material are different.
11. The micro-hybrid battery system of claim 10, wherein the first
anode active material comprises lithium titanate (LTO), the second
anode active material comprises graphite, and the first and second
cathode active materials are lithium nickel manganese cobalt oxide
(NMC).
12. The micro-hybrid battery system of claim 2, wherein the energy
storage unit comprises an ultracapacitor or an additional lithium
ion battery module.
13. The micro-hybrid battery system of claim 1, wherein the first
and second lithium ion battery cells are electrically coupled in
series.
14. The micro-hybrid battery system of claim 13, comprising a
plurality of lithium ion battery cells having the first and second
lithium ion battery cells, wherein the plurality of lithium ion
battery cells comprises a different number of the first lithium ion
battery cells and the second lithium ion battery cells.
15. A micro-hybrid battery system, comprising: a first battery
module; and a lithium ion battery module electrically connected in
parallel with the first battery module and comprising multiple
groups of lithium ion battery cells and multiple different lithium
ion battery chemistries, wherein each of the multiple groups of
lithium ion battery cells corresponds to one of the multiple
different lithium ion battery chemistries; wherein the first
battery module and the lithium ion battery module are voltage
matched.
16. The micro-hybrid battery system of claim 15, wherein each of
the multiple groups of lithium ion battery cells comprises one or
more lithium ion battery cells.
17. The micro-hybrid battery system of claim 15, wherein the
multiple groups of lithium ion battery cells are connected with one
another in series, in parallel, or a combination thereof.
18. The micro-hybrid battery system of claim 15, wherein the
multiple groups of lithium ion battery cells are configured such
that the lithium ion battery module has a voltage profile of
voltage as a function of state of charge (SOC) that overlaps a
voltage window of the first battery module, the overlap occurring
within a first SOC range of the voltage profile in which the
lithium ion battery module is intended to operate within the
micro-hybrid battery system, wherein the voltage window of the
first battery module corresponds to a second SOC range in which the
first battery module is intended to operate within the micro-hybrid
battery system.
19. The micro-hybrid battery system of claim 18, wherein the
multiple groups of lithium ion battery cells are configured such
that the voltage profile of the lithium ion battery module overlaps
the voltage window of the first battery module within a lower half
of the SOC range.
20. The micro-hybrid battery system of claim 18, wherein the
multiple groups of lithium ion battery cells are configured such
that the voltage profile of the lithium ion battery module overlaps
the voltage window of the first battery module within an upper half
of the SOC range.
21. The micro-hybrid battery system of claim 15, wherein the first
battery module comprises an ultracapacitor or an additional lithium
ion battery module.
22. A method for manufacturing a battery system, comprising:
assembling multiple lithium ion battery cells into a lithium ion
battery module such that a first lithium ion battery cell of the
multiple lithium ion battery cells comprises a different lithium
ion battery chemistry from a second lithium ion battery cell of the
multiple lithium ion battery cells, wherein assembling the multiple
lithium ion battery cells into the lithium ion battery module
comprises electrically connecting the first lithium ion battery
cell and the second lithium ion battery cell; and electrically
connecting the lithium ion battery module with an additional
battery module in parallel, wherein the multiple lithium ion
battery cells are configured such that the lithium ion battery
module is voltage matched with the additional battery module.
23. The method of claim 22, wherein assembling the multiple lithium
ion battery cells into the lithium ion battery module comprises
electrically connecting the multiple battery cells using series
connections, parallel connections, or a combination thereof.
24. The method of claim 22, wherein electrically connecting the
lithium ion battery module with the additional battery module in
parallel comprises electrically connecting the lithium ion battery
module with a 12V automotive lead-acid battery.
25. The method of claim 22, wherein the multiple lithium ion
battery cells are configured such that the lithium ion battery
module has a voltage profile of voltage as a function of state of
charge (SOC) that overlaps a voltage window of the additional
battery module, the overlap occurring within a first SOC range of
the voltage profile in which the lithium ion battery module is
intended to operate within the battery system, wherein the voltage
window of the additional battery module corresponds to a second SOC
range in which the additional battery module is intended to operate
within the battery system.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from and the benefit of
U.S. Provisional Application Ser. No. 61/923,118, entitled
"COMBINATORIAL CHEMISTRIES FOR MATCHING THE VOLTAGE OF MULTIPLE
ENERGY STORAGE SOURCES", filed Jan. 2, 2014, which is hereby
incorporated by reference in its entirety.
BACKGROUND
[0002] The present disclosure relates generally to the field of
batteries and battery modules. More specifically, the present
disclosure relates to active material in lithium ion
electrochemical cells.
[0003] This section is intended to introduce the reader to various
aspects of art that may be related to various aspects of the
present disclosure, which are described and/or claimed below. This
discussion is believed to be helpful in providing the reader with
background information to facilitate a better understanding of the
various aspects of the present disclosure. Accordingly, it should
be understood that these statements are to be read in this light,
and not as admissions of prior art.
[0004] A vehicle that uses one or more battery systems for
providing all or a portion of the motive power for the vehicle can
be referred to as an xEV, where the term "xEV" is defined herein to
include all of the following vehicles, or any variations or
combinations thereof, that use electric power for all or a portion
of their vehicular motive force. For example, xEVs include electric
vehicles (EVs) that utilize electric power for all motive force. As
will be appreciated by those skilled in the art, hybrid electric
vehicles (HEVs), also considered xEVs, combine an internal
combustion engine propulsion system and a battery-powered electric
propulsion system, such as 48 Volt (V) or 130V systems. The term
HEV may include any variation of a hybrid electric vehicle. For
example, full hybrid systems (FHEVs) may provide motive and other
electrical power to the vehicle using one or more electric motors,
using only an internal combustion engine, or using both. In
contrast, mild hybrid systems (MHEVs) disable the internal
combustion engine when the vehicle is idling and utilize a battery
system to continue powering the air conditioning unit, radio, or
other electronics, as well as to restart the engine when propulsion
is desired. The mild hybrid system may also apply some level of
power assist, during acceleration for example, to supplement the
internal combustion engine. Mild hybrids are typically 96V to 130V
and recover braking energy through a belt or crank integrated
starter generator. Further, a micro-hybrid electric vehicle (mHEV)
also uses a "Stop-Start" system similar to the mild hybrids, but
the micro-hybrid systems of a mHEV may or may not supply power
assist to the internal combustion engine and operates at a voltage
below 60V. For the purposes of the present discussion, it should be
noted that mHEVs typically do not technically use electric power
provided directly to the crankshaft or transmission for any portion
of the motive force of the vehicle, but an mHEV may still be
considered as an xEV since it does use electric power to supplement
a vehicle's power needs when the vehicle is idling with internal
combustion engine disabled and recovers braking energy through an
integrated starter generator. In addition, a plug-in electric
vehicle (PEV) is any vehicle that can be charged from an external
source of electricity, such as wall sockets, and the energy stored
in the rechargeable battery packs drives or contributes to drive
the wheels. PEVs are a subcategory of EVs that include all-electric
or battery electric vehicles (BEVs), plug-in hybrid electric
vehicles (PHEVs), and electric vehicle conversions of hybrid
electric vehicles and conventional internal combustion engine
vehicles.
[0005] xEVs as described above may provide a number of advantages
as compared to more traditional gas-powered vehicles using only
internal combustion engines and traditional electrical systems,
which are typically 12V systems powered by a lead acid battery. For
example, xEVs may produce fewer undesirable emission products and
may exhibit greater fuel efficiency as compared to traditional
internal combustion vehicles and, in some cases, such xEVs may
eliminate the use of gasoline entirely, as is the case of certain
types of EVs or PEVs.
[0006] As technology continues to evolve, there is a need to
provide improved power sources, particularly battery modules, for
such vehicles. For example, a battery system may include multiple
battery modules that may be connected with one another using a
variety of connecting strategies. In many such systems, battery
modules may incorporate battery cells of a certain configuration to
achieve a desired result for the battery modules. For example, cell
sizes, shapes, chemistries, terminal configurations, and so on, may
be chosen for a specific application. Unfortunately, many battery
systems are constrained to one specific battery cell configuration,
which can hinder design flexibility. For example, it is now
recognized that the design flexibility of a battery module in a
battery system may be limited due to the choice of battery cells
having the same cell chemistry. Accordingly, it may be desirable to
provide more design opportunities of a battery module.
SUMMARY
[0007] A summary of certain embodiments disclosed herein is set
forth below. It should be understood that these aspects are
presented merely to provide the reader with a brief summary of
these certain embodiments and that these aspects are not intended
to limit the scope of this disclosure. Indeed, this disclosure may
encompass a variety of aspects that may not be set forth below.
[0008] The present disclosure relates to a micro-hybrid battery
system. The micro-hybrid battery system includes a lithium ion
battery module configured to be coupled to an electrical load. The
lithium ion battery module includes a housing. The lithium ion
battery module also includes a first lithium ion battery cell
disposed in the housing and having a first active material
chemistry including a first cathode active material and a first
anode active material. The lithium ion battery module also includes
a second lithium ion battery cell electrically connected to the
first lithium ion battery cell and disposed in the housing. The
second lithium ion battery cell has a second active material
chemistry including a second cathode active material and a second
anode active material. The first and second active material
chemistries are different such that the first and second lithium
ion battery cells have different open circuit voltages.
[0009] The present disclosure also relates to a micro-hybrid
battery system. The micro-hybrid battery system includes a first
battery module. The micro-hybrid battery system also includes a
lithium ion battery module electrically connected in parallel with
the first battery module and including multiple groups of lithium
ion battery cells and multiple different lithium ion battery
chemistries. Each of the multiple groups of lithium ion battery
cells corresponds to one of the multiple different lithium ion
battery chemistries. The first battery module and the lithium ion
battery module are voltage matched.
[0010] The present disclosure further relates to a method for
manufacturing a battery system. The method includes assembling
multiple lithium ion battery cells into a lithium ion battery
module such that a first lithium ion battery cell of the multiple
lithium ion battery cells comprises a different lithium ion battery
chemistry from a second lithium ion battery cell of the multiple
lithium ion battery cells. Assembling the multiple lithium ion
battery cells into the lithium ion battery module includes
electrically connecting the first lithium ion battery cell and the
second lithium ion battery cell. The method also includes
electrically connecting the lithium ion battery module with an
additional battery module in parallel. The multiple lithium ion
battery cells are configured such that the lithium ion battery
module is voltage matched with the additional battery module.
DRAWINGS
[0011] These and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0012] FIG. 1 is a perspective view of a vehicle (e.g., a mHEV)
having a battery system, in accordance with an embodiment of the
present disclosure;
[0013] FIG. 2 is a cutaway schematic view of the vehicle of FIG. 1
having a battery system, in accordance with an embodiment of the
present disclosure;
[0014] FIG. 3 is a schematic diagram of an embodiment of the energy
storage component that includes multiple voltage matched battery
modules, in accordance with an embodiment of the present
disclosure;
[0015] FIG. 4 is a chart of voltage characteristics for various
battery modules, in accordance with an embodiment of the present
disclosure;
[0016] FIG. 5 is a chart of voltage characteristics for various
battery modules, in accordance with an embodiment of the present
disclosure; and
[0017] FIG. 6 is a flow diagram of a method for making an energy
storage component that includes multiple voltage matched battery
modules, in accordance with the present disclosure.
DETAILED DESCRIPTION
[0018] One or more specific embodiments of the present techniques
will be described below. In an effort to provide a concise
description of these embodiments, not all features of an actual
implementation are described in the specification. It should be
appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0019] As discussed above, vehicle technology has improved to
increase fuel economy and/or reduce undesirable emissions compared
to more traditional gas-powered vehicles. For example, micro-hybrid
vehicles disable the vehicle's internal combustion engine when the
vehicle is idling. While the vehicle's internal combustion engine
is disabled, the battery system may continue supplying power to the
vehicle's electrical system, which may include the vehicle's radio,
air conditioning, electronic control units, and the like.
Additionally, regenerative braking vehicles capture and store
electrical power generated when the vehicle is braking or coasting.
In some embodiments, the generated electrical power may then be
utilized to supply power to the vehicle's electrical system. In
other embodiments, the generated electrical power may be utilized
to stabilize voltage during high demand, for example in
regenerative storage systems.
[0020] Based on the advantages over traditional gas-power vehicles,
manufactures, which generally produce traditional gas-powered
vehicles, may desire to utilize improved vehicle technologies
(e.g., micro-hybrid technology or regenerative braking technology)
within their vehicle lines. These manufactures often utilize one of
their traditional vehicle platforms as a starting point. Generally,
traditional gas-powered vehicles are designed to utilize 12 V
battery systems (e.g., operating voltages between 7-18 V), such as
a single 12 V lead-acid battery. Accordingly, since traditional
gas-powered vehicles are designed to utilize 12 V battery systems,
a 12 V lithium ion battery may be used to supplement a 12 V
lead-acid battery. More specifically, the 12 V lithium ion battery
may be used to more efficiently capture electrical energy generated
during regenerative braking and subsequently supply electrical
energy to power the vehicle's electrical system. Additionally, in a
mHEV, the internal combustion engine may be disabled when the
vehicle is idle. Accordingly, the 12 V lithium ion battery may be
used to crank (e.g., restart) the internal combustion engine when
propulsion is desired.
[0021] Present embodiments include physical battery module
features, assembly components, manufacturing and assembling
techniques, and so forth, that facilitate providing more design
opportunities for battery modules and systems, especially for 12 V
battery systems, using a combination of lithium ion chemistries. As
used herein, "battery module" is intended to describe energy
storage devices that utilize various chemical reactions to store
and/or distribute electrical power. As will be described in more
detail below, a battery system may include a first battery module
(e.g., a lead-acid battery) and a second battery module (e.g., a
lithium ion battery). Each battery module may include multiple
battery cells (e.g., connected with one another in series, in
parallel, or a combination thereof). For example, a 12 V lithium
ion battery may include six in-series lithium nickel manganese
cobalt oxide/lithium-titanate (NMC/LTO) lithium ion battery cells,
each of which may have a voltage range of about 2 to 2.8 V.
Characteristics, such as a voltage profile (e.g., open circuit
voltage as a function of state of charge), of each battery module
may depend on the configuration of battery cells within each
battery module (e.g., in series or parallel) and the battery
chemistries selected for the battery cells.
[0022] To facilitate supplementing the first battery module with
the second battery module, the first battery module and the second
battery module may be connected in various parallel architectures.
For example, the battery system may utilize a passive architecture,
where the first battery module and the second battery module may be
directly coupled to terminals of a vehicle bus. When the first
battery module and the second battery module are connected in
parallel, the two battery modules may be voltage matched for
operation. For example, a voltage profile of the second battery
module may overlap with a voltage window of the first battery
module within an operating window of a battery system in which the
first battery module and the second battery module are intended to
function. In accordance with certain aspects of the present
disclosure, the voltage window of the first battery module may be
determined by a state of charge (SOC) range in which the first
battery module is operated within the battery system. In such
embodiments, the second battery module is considered to be "voltage
matched" to the first battery module when the overlap of the
voltage profile and the voltage window occurs in a desired SOC
range in which the second battery module is operated within the
battery system.
[0023] In accordance with the present disclosure, systems and
methods are provided for matching the voltage of multiple battery
modules in a battery system based on a combination of lithium ion
chemistries, for example by incorporating multiple lithium ion
chemistries into a single lithium ion battery module. As will be
discussed in greater detail below, both the numbers and the
chemistries of the battery cells (e.g., chemistries of lithium ion
battery cells) may be varied for a second battery module (e.g.,
varied within a single battery module) to voltage match a first
battery module. As such, the design flexibility for battery modules
may be greatly increased. Accordingly, better performance and/or
lower cost in battery system design may be achieved. In addition,
as will be discussed below, not only the output voltage but also
the state of charge may be considered in matching the second
battery module to the first battery module in accordance with the
present disclosure. Accordingly, the overall performance, such as
charging efficiency, of the battery system may be enhanced.
[0024] To simplify the following discussion, the present techniques
will be described in relation to a battery system with a 12 V
lead-acid battery (e.g., as a first battery module) and a 12 V
lithium ion battery (e.g., as a second battery module). However,
the present techniques are also applicable to other battery
systems, such as a battery system with a different output voltage
(e.g., 48 V, 96 V).
[0025] With the foregoing in mind, FIG. 1 is a perspective view of
an embodiment of a vehicle 10, such as a micro-hybrid vehicle.
Although the following discussion is presented in relation to
micro-hybrid vehicles, the techniques described herein are
adaptable to other vehicles that capture/store electrical energy
with a battery, which may include electric-powered and gas-powered
vehicles.
[0026] It may be desirable for a battery system 12 to be largely
compatible with traditional vehicle designs. Accordingly, the
battery system 12 may be placed in a location in the vehicle 10
that would have housed a traditional battery system. For example,
as illustrated, the vehicle 10 may include the battery system 12
positioned similarly to a lead-acid battery of a typical
combustion-engine vehicle (e.g., under the hood of the vehicle 10).
Furthermore, as will be described in more detail below, the battery
system 12 may be positioned to facilitate managing temperature of
the battery system 12. For example, in some embodiments,
positioning a battery system 12 under the hood of the vehicle 10
may enable an air duct to channel airflow over the battery system
12 and cool the battery system 12.
[0027] A more detailed view of the battery system 12 is described
in FIG. 2. As depicted, the battery system 12 includes an energy
storage component 14 coupled to an ignition system 16, an
alternator 18, a vehicle console 20, and optionally to an electric
motor 22. Generally, the energy storage component 14 may
capture/store electrical energy generated in the vehicle 10 and
output electrical energy to power electrical devices in the vehicle
10.
[0028] In other words, the battery system 12 may supply power to
components of the vehicle's electrical system, which may include
radiator cooling fans, climate control systems, electric power
steering systems, active suspension systems, auto park systems,
electric oil pumps, electric super/turbochargers, electric water
pumps, heated windscreen/defrosters, window lift motors, vanity
lights, tire pressure monitoring systems, sunroof motor controls,
power seats, alarm systems, infotainment systems, navigation
features, lane departure warning systems, electric parking brakes,
external lights, or any combination thereof. In the depicted
embodiment, the energy storage component 14 supplies power to the
vehicle console 20 and the ignition system 16, which may be used to
start (e.g., crank) the internal combustion engine 24.
[0029] Additionally, the energy storage component 14 may capture
electrical energy generated by the alternator 18 and/or the
electric motor 22. In some embodiments, the alternator 18 may
generate electrical energy while the internal combustion engine 24
is running. More specifically, the alternator 18 may convert the
mechanical energy produced by the rotation of the internal
combustion engine 24 into electrical energy. Additionally or
alternatively, when the vehicle 10 includes an electric motor 22,
the electric motor 22 may generate electrical energy by converting
mechanical energy produced by the movement of the vehicle 10 (e.g.,
rotation of the wheels) into electrical energy. Thus, in some
embodiments, the energy storage component 14 may capture electrical
energy generated by the alternator 18 and/or the electric motor 22
during regenerative braking. As such, the alternator and/or the
electric motor 22 are generally referred to herein as a
regenerative braking system.
[0030] To facilitate capturing and supplying electric energy, the
energy storage component 14 may be electrically coupled to the
vehicle's electric system via a bus 26. For example, the bus 26 may
enable the energy storage component 14 to receive electrical energy
generated by the alternator 18 and/or the electric motor 22.
Additionally, the bus 26 may enable the energy storage component 14
to output electrical energy to the ignition system 16 and/or the
vehicle console 20. Accordingly, when a 12 V battery system 12 is
used, the bus 26 may carry electrical power typically between 8-18
V.
[0031] Additionally, as depicted, the energy storage component 14
may include multiple battery modules. For example, in the depicted
embodiment, the energy storage component 14 includes a lithium ion
(e.g., a second) battery module 28 and a lead-acid (e.g., a first)
battery module 30, which each includes one or more battery cells.
In other embodiments, the energy storage component 14 may include
any number of battery modules. Additionally, although the lithium
ion battery module 28 and lead-acid battery module 30 are depicted
adjacent to one another, they may be positioned in different areas
around the vehicle. For example, the lead-acid battery module may
be positioned in or about the interior of the vehicle 10 while the
lithium ion battery module 28 may be positioned under the hood of
the vehicle 10.
[0032] In some embodiments, the energy storage component 14 may
include multiple battery modules to utilize multiple different
battery chemistries. For example, when the lithium ion battery
module 28 is used, performance of the battery system 12 may be
improved since the lithium ion battery chemistry generally has a
higher coulombic efficiency and/or a higher power charge acceptance
rate (e.g., higher maximum charge current or charge voltage) than
the lead-acid battery chemistry. As such, the capture, storage,
and/or distribution efficiency of the battery system 12 may be
improved.
[0033] To facilitate controlling the capturing and storing of
electrical energy, the battery system 12 may additionally include a
control module 32. More specifically, the control module 32 may
control operations of components in the battery system 12, such as
relays (e.g., switches) within energy storage component 14, the
alternator 18, and/or the electric motor 22. For example, the
control module 32 may regulate amount of electrical energy
captured/supplied by each battery module 28 or 30 (e.g., to de-rate
and re-rate the battery system 12), perform load balancing between
the battery modules 28 and 30, determine a state of charge of each
battery module 28 or 30, determine temperature of each battery
module 28 or 30, control voltage output by the alternator 18 and/or
the electric motor 22, and the like.
[0034] Accordingly, the control unit 32 may include one or more
processors 34 and one or more memory 36. More specifically, the one
or more processors 34 may include one or more application specific
integrated circuits (ASICs), one or more field programmable gate
arrays (FPGAs), one or more general purpose processors, or any
combination thereof. Additionally, the one or more memory 36 may
include volatile memory, such as random access memory (RAM), and/or
non-volatile memory, such as read-only memory (ROM), optical
drives, hard disc drives, or solid-state drives. In some
embodiments, the control unit 32 may include portions of a vehicle
control unit (VCU) and/or a separate battery control module.
Furthermore, as depicted, the lithium ion battery module 28 and the
lead-acid battery module 30 are connected in parallel across their
terminals. In other words, the lithium ion battery module 28 and
the lead-acid module 30 may be coupled in parallel to the vehicle's
electrical system via the bus 26.
[0035] As noted above, the first battery module 30 and the second
battery module 28 may be connected in various parallel
architectures. For example, FIG. 3 illustrates schematically an
embodiment of the energy storage component 14 where the first
battery module 30 and the second battery module 28 are connected in
parallel with one another and directly coupled to terminals (e.g.,
a first terminal 38 and a second terminal 40) of the energy storage
component 14. The battery terminals 38, 40 may output power stored
in the energy storage component 14 to provide power to electrical
devices in the vehicle 10. Additionally, the battery terminals 38,
40 may also provide power to the energy storage component 14 to
enable the first battery module 30 and the second battery module 28
to receive charge from, for example, the alternator 18 and/or power
the electric motor 22. In some embodiments, the second terminal 40
may provide a ground connection, and the first terminal 38 may
provide a positive voltage ranging between 7-18 V.
[0036] As illustrated, the first battery module 30 may include m
battery cells 42 (e.g., connected in series), where m may be any
integer number, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. The
first battery module 30 may have a first voltage profile (e.g.,
open circuit voltage as a function of SOC). For example, the first
battery module 30 may be a 12 V lead-acid battery that includes m=6
lead-acid battery cells 42 and may have the open circuit voltage
ranging between, for example, 11.2-13.0 V in a SOC range of between
approximately 0% to 100%. The second battery module 28 may have a
second voltage profile. By way of example, the second battery
module 28 may have voltage ranging between 11.8-16 V in a SOC range
of between approximately 0% to 100%.
[0037] In accordance with the present disclosure, the second
battery module 28 may be voltage matched to the first battery
module 30 by varying both the number and the chemistry of the
battery cells within the second battery module 28. As illustrated,
the second battery module 28 includes n battery cells 44 (e.g.,
44a, 44b, 44c, and so on) connected in series, where n may be any
integer number, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. In
one aspect, all of the battery cells 44 in the second battery
module 28 do not have the same chemistry. In other words, at least
one of the battery cells 44 in the second battery module 28 has a
different chemistry from at least one of the other battery cells 44
in the second battery module 28. For instance, battery cell 44a may
have a different battery chemistry (e.g., a different combination
of a cathode active material and an anode active material) than
battery cell 44b.
[0038] Each of the battery cells 44 in the second battery module 28
may be any type of lithium ion battery cells, thereby having any
suitable chemistry (e.g., a combination of cathode active material
and anode active material). As used herein, a lithium ion battery
cell may be represented by denoting its main cathode active
material/anode active material. For example, a NMC/LTO battery cell
refers to a battery cell having a lithium nickel manganese cobalt
oxide (NMC) cathode active material and a lithium-titanate (LTO)
anode active material. By way of example, the cathode active
material of any of the battery cells 44 may be a lithium metal
oxide (LMO) component. As used herein, lithium metal oxides may
refer to any class of materials whose formula includes lithium and
oxygen as well as one or more additional metal species (e.g.,
nickel, cobalt, manganese, aluminum, iron, or another suitable
metal). A non-limiting list of example LMOs may include: mixed
metal compositions including lithium, nickel, manganese, and cobalt
ions such as lithium nickel cobalt manganese oxide (NMC) (e.g.,
LiNi.sub.1/3Co.sub.1/3Mn.sub.1/3O.sub.2), lithium nickel cobalt
aluminum oxide (NCA) (e.g.,
LiNi.sub.0.8Co.sub.0.15Al.sub.0.05O.sub.2), lithium cobalt oxide
(LCO) (e.g., LiCoO.sub.2), and lithium metal oxide spinel
(LMO-spinel) (e.g., LiMn.sub.2O.sub.4). The cathode may include
only a single active material (e.g., NMC), or may include a mixture
of materials such as any one or a combination of: NMC, NCA, LCO,
LMO-spinel, and the like. Other cathode active materials may be
utilized in addition to or in lieu of these materials, such as
lithium metal phosphates. Examples of such active materials are
generally defined by the formula LiMPO.sub.4, wherein M is Fe, Ni,
Mn, or Mg. Any one or a combination of these phosphates may be used
as the cathode active material, in addition to or in lieu of any
one or a combination of the lithium metal oxide materials
encompassed by the description above. Thus, the cathode active
material may include any one or a combination of: NMC
(Li.sub.xNi.sub.aMn.sub.bCo.sub.cO.sub.2, x+a+b+c=2),
LiMn.sub.2O.sub.4 (LMO) spinel, NCA
(LiNi.sub.xCo.sub.yAl.sub.zO.sub.2, x+y+z=1),
LiMn.sub.1.5Ni.sub.0.5O.sub.2, LiCoO.sub.2 (LCO), or LiMPO.sub.4,
wherein M is Fe, Ni, Mn, or Mg. The anode active material of any of
the battery cells 44 may generally include any one or a combination
of materials, such as carbon (e.g., graphite), titanium dioxide
(TiOx or otherwise denoted as TiO.sub.2), or lithium titanium
oxide, also referred to herein as LTO (Li.sub.4Ti.sub.5O.sub.12).
The anode active material may include any one or a combination of
these and other active materials.
[0039] Because different battery chemistries may result in
different voltage characteristics (e.g., open circuit voltage) of
battery cells, by including more than one battery chemistry in the
second battery module 28, battery modules can be designed to
benefit from the characteristics of the different chemistries. In
other words, a voltage profile (voltage as a function of SOC) can
be designed to achieve a particular result. The voltage profile may
be designed to be relatively flat within a desired SOC range (an
SOC range in which the second battery module 28 will be operated in
the battery system 12), or may be designed to have steep slopes to
achieve different charging and discharging characteristics within
the desired SOC range and also within a voltage window of the
battery system 12 (a range of voltages in which the battery system
12 is intended to operate). In addition, by varying the number of
the battery cells 44 for each different chemistries, one additional
degree of freedom is provided in selecting battery cells 44 for
voltage matching between the second battery module 28 and the first
battery module 30.
[0040] As such, for the second battery module 28 to voltage match
the first battery module 30, the battery cells 44 of the second
battery module 28 may be selected combinatorially based on the
number (e.g., more than one) of the chemistries and the number of
the battery cells 44. More specifically, the total number of the
battery cells 44 in the battery module 28, the total number (e.g.,
more than one) of chemistries in the battery module 28, and the
number of battery cells 44 for each chemistry may be varied for the
second battery module 28 to voltage match the first battery module
30. By way of example, if the first battery module 30 has an open
circuit voltage of 12 V at a certain SOC, the second battery module
28 may include, in series, two battery cells 44 with a first
chemistry having an open circuit voltage of 3 V, and three battery
cells with a second chemistry having an open circuit voltage of 2
V, which may provide the second battery module 28 with an overall
open circuit voltage of 12 V at the same or a different SOC.
Alternatively, the second battery module 28 may include, in series,
one battery cell 44 with a first chemistry having an open circuit
voltage of 3 V, four battery cells with a second chemistry having
an open circuit voltage of 2 V, and one battery cell 44 with a
third chemistry having an open circuit voltage of 1 V, which may
also provide the second battery module 28 with an open circuit
voltage of 12 V at the same or a different SOC. Also, the voltages
described herein may be open circuit voltages, average voltages
determined at a discharge rate (e.g., C/10), or any other measure
of voltage.
[0041] While in the illustrated embodiment the battery cells 44 in
the second battery module 28 are connected in series with one
another, in some embodiments, the battery cells 44 in the second
battery module 28 may be connected with one another in various
other configurations, such as in parallel, or a combination of in
series and in parallel. For example, multiple battery cells 44
having a same chemistry may be connected with one another in
parallel, and then connected with one or more battery cells 44
having a different chemistry.
[0042] As noted above, the voltage profile of each of the first
battery module 30 and the second battery module 28 may depend on
their respective states of charge. FIG. 4 is a chart 46 of voltage
characteristics (e.g., voltage profiles) for various battery
modules. More specifically, FIG. 4 is a plot depicting the open
circuit voltage of a first battery module 30 or a second battery
module 28 (utilizing various combinations of numbers and
chemistries of the battery cells 44) over the respective battery
module's total state of charge range (e.g., from 0% state of charge
to 100% SOC). FIG. 4 illustrates the SOC (in %) on the X-axis and
the open circuit voltage (in V) on the Y-axis.
[0043] As illustrated, the chart 46 includes a lead-acid (PbA)
voltage profile 48 depicting the open circuit voltage for the first
battery module 30 (e.g., the lead-acid battery) in a range of SOC
(e.g., 0% to 100%). The chart 46 also includes various voltage
profiles depicting the open circuit voltages in a range of SOC
(e.g., 0% to 100%) for the second battery module 28 (e.g., the
lithium ion battery) utilizing various combinations of numbers and
chemistries of the battery cells 44, including a 4-NMC/graphite
voltage profile 50, a 4-LMO/graphite voltage profile 52, a
6-NMC/LTO voltage profile 54, a 6-LMO/LTO voltage profile 56, and a
1-NMC/graphite+4-NMC/LTO voltage profile 58. As used herein,
"4-NMC/graphite" refers to the second battery module 28 having four
NMC/graphite battery cells 44; "4-LMO/graphite" refers to the
second battery module 28 having four LMO/graphite battery cells 44;
"6-NMC/LTO" refers to the second battery module 28 having six
NMC/LTO battery cells 44; "6-LMO/LTO" refers to the second battery
module 28 having six LMO/LTO battery cells 44; and
"1-NMC/graphite+4-NMC/LTO" refers to the second battery module 28
having one NMC/graphite battery cell 44 and four NMC/LTO battery
cells 44.
[0044] As illustrated in FIG. 4, the voltage of each battery module
may vary with its SOC. For the purposes of explaining an aspect of
the present disclosure, the first battery module 30 is described
below as being a, lead-acid (PbA) battery. For the PbA battery
(first battery module 30 in FIG. 4), the PbA voltage profile 48
shows that the first battery module 30 at 0% state of charge may
have a voltage of 11.2 V, at 50% state of charge may have a voltage
of 12.2 V, and at 100% state of charge may have a voltage of 13.0
V. In other words, the first battery module 30 has a voltage range
of 11.2-13.0 V. FIG. 4 also includes a voltage window 62 of the
first battery module 30. In the illustrated embodiment, the voltage
window 62 includes an upper voltage limit 64 (e.g., about 13.0 V,
corresponding to about 100% SOC) and a lower voltage limit 66
(e.g., about 12.6 V, corresponding to about 80% SOC). However, it
should be noted that other embodiments of the first battery module
30 may have a different range for the voltage window 62 (e.g., with
any suitable upper voltage limit 64 and lower voltage limit 66,
covering any suitable range of SOC), depending on the chemistry of
the first battery module 30.
[0045] As also illustrated in FIG. 4, the second battery module 28
may be designed to include various combinations of battery cell
chemistries, resulting in different voltage characteristics (e.g.,
whether and how the voltage profile of the second battery module 28
results in voltage matching to the first battery module 30). For
example, the 4-NMC/graphite voltage profile 50 does not overlap
with the voltage window 62 (e.g., 12.6-13.0 V) as the
4-NMC/graphite voltage profile 50 has its lowest voltage of
approximately 13.6 V at 0% SOC. Accordingly, in this example, the
first battery module 30 and the second battery module 28 are not
voltage matched (e.g., with respect to the voltage window 62 of the
first battery module 30). Similarly, the 4-LMO/graphite voltage
profile 52 does not overlap with the voltage window 62 (e.g.,
12.6-13.0 V) as the 4-LMO/graphite voltage profile 52 has its
lowest voltage of approximately 14.0 V at 0% SOC. Accordingly,
again, the first battery module 30 and the second battery module 28
are not voltage matched. When the second battery module 28 is not
voltage matched to the first battery module 30, the energy storage
component 14 may not function efficiently, for example, during
charging, the second battery module 28 may not have good charge
accepting capacity (e.g., the voltage of the second battery module
28 at 0% SOC is higher than the upper voltage limit 64 of the
voltage window 62 of the first battery module 30).
[0046] The second battery module 28 having six NMC/LTO battery
cells 44 and the second battery module 28 having six LMO/LTO
battery cells 44 are both better voltage matched to the first
battery module 30 compared to the above two examples: (1) the
second battery module 28 having four NMC/graphite battery cells 44
and (2) the second battery module 28 having four LMO/graphite
battery cells 44. For example, the 6-NMC/LTO voltage profile 54
overlaps with the voltage window 62 (e.g., 12.6-13.0 V) in a SOC
range of about 10% to 25% as the 6-NMC/LTO voltage profile 54 has a
voltage of approximately 12.6 V at about 10% SOC and a voltage of
approximately 13.0 V at about 25% SOC. However, operating the
second battery module 28 (for the embodiment having six NMC/LTO
battery cells 44) in the range of relatively low SOC (e.g., below
25% SOC) may result in low discharge capability, which can, in
certain implementations, decrease the overall performance of the
battery system 12.
[0047] Similarly, as illustrated in FIG. 4, the 6-LMO/LTO voltage
profile 56 overlaps with the voltage window 62 (e.g., 12.6-13.0 V)
in a SOC range of about 0% to 2% as the 6-LMO/LTO voltage profile
56 has a voltage of approximately 12.6 V at about 0% SOC and a
voltage of approximately 13.0 V at about 2% SOC. Operating the
second battery module 28 (having six LMO/LTO battery cells 44) in
the range of relatively low SOC (e.g., below 2% SOC), again, may
result in low discharge capability, therefore decreasing the
overall performance of the energy storage component 14.
[0048] Comparatively, FIG. 4 illustrates that the second battery
module 28 having one NMC/graphite battery cell 44 and four NMC/LTO
battery cells 44 is better voltage matched to the first battery
module 30. For example, the 1-NMC/graphite+4-NMC/LTO voltage
profile 58 overlaps with the voltage window 62 (e.g., 12.6-13.0 V)
in a SOC range of about 45% to 60% as the 1-NMC/graphite+4-NMC/LTO
voltage profile 58 has a voltage of approximately 12.6 V at about
45% SOC and a voltage of approximately 13.0 V at about 60% SOC.
Because the second battery module 28 having one NMC/graphite
battery cell 44 and four NMC/LTO battery cells 44 is voltage
matched with the first battery module 30 (e.g., with respect to the
voltage window 62) about 50% SOC (e.g., between about 45% to 50%
SOC), the second battery module 28 may have a good balance of both
charging and discharging capacity, which may result in an improved
performance of the energy storage component 14.
[0049] Accordingly, to improve voltage matching of the second
battery module 28 to the first battery module 30, the particular
combination of the battery cells 44 (e.g., the number and the
chemistries) of the second battery module 28 may be at least
partially based on overlapping between voltage characteristics
(e.g., the open circuit voltage profile) of the second battery
module 28 and voltage characteristics (e.g., the voltage window) of
the first battery module 30. Indeed, as discussed above, the second
battery module 28 having one NMC/graphite battery cell 44 and four
NMC/LTO battery cells 44 is better voltage matched to the first
battery module 30 compared to other examples of the second battery
module (e.g., having four NMC/graphite battery cells 44, having
four LMO/graphite battery cells 44, having six NMC/LTO battery
cells 44, and having six LMO/LTO battery cells 44) because the open
circuit voltage of the second battery module 28 having one
NMC/graphite battery cell 44 and four NMC/LTO battery cells 44
overlap with the voltage window 62 of the first battery module 30
at a relatively middle portion of the SOC range (e.g., between
about 45% to 60%). However, it should be noted that in some
embodiments, it may be desirable to have a second battery module 28
that voltage matches the first battery module 30 at any suitable
range (or value) of SOC, such as between about 0% to 100%, between
about 10% to 90%, between about 20% to 80%, between about 30% to
70%, between about 40% to 60%, between about 0% to 20%, between
about 20% to 40%, between about 60% to 80%, or between about 80% to
100%. Thus, the combination of battery cells 44, including the
numbers and the chemistries, for the second battery module 28 may
be based on the voltage match between the second battery module 28
and the first battery module 30 at a desired SOC range or about a
desired SOC value.
[0050] It should be noted that while one example (e.g., the second
battery module 28 having one NMC/graphite battery cell 44 and four
NMC/LTO battery cells 44) is provided in FIG. 4, the method
described herein may be used to select or design various other
combinations of battery cells 44, including the total number of the
battery cells 44 in the second battery module 28, the total number
(e.g., more than one) of chemistries in the second battery module
28, and the number of battery cells 44 for each chemistry, for
voltage matching of the second battery module 28 and the first
battery module 30.
[0051] In accordance with another aspect of present disclosure,
particular combinations (e.g., the numbers and chemistries) of the
battery cells 44 in the second battery module 28 may be based on
matching the voltage characteristics (e.g., the open circuit
voltage profile) of the second battery module 28 to an operating
window of the energy storage component 14 in which the first
battery module 30 and the second battery module 20 are intended to
function. The operating window of the energy storage component 14
may include a range of voltage (e.g., specified by a manufacture)
in which the energy storage component 14 generally operates. The
operating window of the energy storage component 14 may depend on
characteristics (e.g., open circuit profile) of the first battery
module 30. By way of example, when the first battery module 30 is a
12 V lead-acid battery module, which has an open circuit range of
11.2-13.0 V, the operating window of the energy storage component
14 may be, for example, 10.5-16.0 V, 12.0-14.8 V, 12.0-14.4 V, or
12.0-14.0 V. The combinations (e.g., the numbers and chemistries)
of the battery cells 44 in the second battery module 28 may be
based on the matching (e.g., overlap) of the open circuit voltage
profile of the second battery module 28 and the operating window of
the energy storage component 14.
[0052] For example, FIG. 5 is a chart 68 of voltage characteristics
for various second battery modules 28 with respect to an operating
window 70 of the energy storage component 14. More specifically,
FIG. 5 depicts the open circuit voltage profiles of various second
battery modules 28 (same as in FIG. 4) with respect to the
operating voltage window 70 that has an upper voltage limit 72 of
about 14.0 V and a lower voltage limit 74 of about 12.0 V. However,
as noted above, the energy storage component 14 may have any
suitable operating window 70 (e.g., with any suitable upper voltage
limit 72 and lower voltage limit 74) that may depend on
characteristics (e.g., open circuit profile) of the first battery
module 30.
[0053] A specific combination (e.g., the numbers and chemistries)
of the battery cells 44 within the second battery module 28 may
result in a particular open circuit profile of the second battery
module 28, which may overlap with the operating window 70 in a
particular manner (e.g., overlapping in a particular range of SOC).
The particular manner of such overlapping may in turn determine the
performance of the second battery module 28 (and consequently the
energy storage component 14). Accordingly, combinations (e.g., the
numbers and chemistries) of the battery cells 44 may be tuned so as
to provide a particular second battery module 28 for a desired
performance. More specifically, if a higher charging power of the
second battery module 28 is desired, the combination of the battery
cells 44 may be provided such that the voltage profile overlaps a
respective voltage profile (or respective voltage window) of the
first battery module 30 at a relatively lower SOC range (e.g.,
about 0% to 30%, about 5% to 25%, or about 10% to 20%), so that the
second battery module 28 has a higher charging capability within
the operating window 70. If a higher discharging power of the
second battery module 28 is desired, the combination of the battery
cells 44 may be provided such that the voltage profile overlaps a
respective voltage profile (or respective voltage window) of the
first battery module 30 at a relatively higher SOC range (e.g.,
about 70% to 100%, about 75% to 95%, or about 80% to 90%), so that
the second battery module 28 has a higher discharging capability
within the operating window 70. If a balance of high charging and
discharging power of the second battery module 28 is desired, the
combination of the battery cells 44 (e.g., combinations of battery
cells 44a, 44b, 44c, and so on) may be provided such that the
voltage profile overlaps a respective voltage profile (or
respective voltage window) of the first battery module 30 at a
relatively middle portion of the SOC range (e.g., about 30% to 70%,
about 35% to 65%, about 40% to 60%, or about 45% to 55%), so that
the second battery module 28 has a balanced charging and
discharging capability within the operating window 70.
[0054] By way of specific examples, FIG. 5 illustrates that the
4-LMO/graphite voltage profile 52 barely overlaps with the
operating window 70 (e.g., 12.0-14.0 V) as the 4-LMO/graphite
voltage profile 52 has its lowest voltage of approximately 14.0 V
at 0% SOC. Accordingly, in this example, the second battery 28 may
not provide a good charging capacity to the energy storage
component 14 because the second battery 28 barely has any charging
capacity (e.g., about 0% SOC) at the upper voltage limit 72 of the
operating window 70.
[0055] Also as illustrated in FIG. 5, both of the 4-NMC/graphite
voltage profile 50 and the 6-LMO/LTO voltage profile 56 overlap
with the operating window 70 (e.g., 12.0-14.0 V) in a SOC range of
about 0% to 5%. The profiles 50, 56 show that although the
4-NMC/graphite and 6-LMO/LTO battery module examples are a better
match than the 4-LMO/graphite battery module example, they still
have a limited charging and discharging power within the operating
window 70, and may not function efficiently in this window 70.
[0056] On the other hand, both the second battery module 28 having
six NMC/LTO battery cells 44 and the second battery module 28
having one NMC/graphite battery cell 44 and four NMC/LTO battery
cells 44 may provide a more efficient overall performance of the
energy storage component 14 compared to the above three second
battery modules 28. For example, the 6-NMC/LTO voltage profile 54
overlaps with the operating window 70 (e.g., 12.0-14.0 V) in a SOC
range of about 0% to 70% (e.g., with an overall about 70% operating
SOC). The 1-NMC/graphite+4-NMC/LTO voltage profile 58 overlaps with
the operating window 70 (e.g., 12.0-14.0 V) in a SOC range of about
10% to 90% (e.g., with an overall about 80% operating SOC). As
such, because both the second battery module 28 having six NMC/LTO
battery cells 44 and the second battery module 28 having one
NMC/graphite battery cell 44 and four NMC/LTO battery cells 44 have
voltage profiles that respectively overlap with the operating
window 70 in a relatively middle portion of the SOC range, both may
provide a relatively balanced charging and discharging power. In
addition, because both of the second battery modules 28 have a
relatively large overall SOC operating range (e.g., 70% and 80%,
respectively) within the operating window 70, both may result in
more efficient overall performance of the energy storage component
14.
[0057] FIG. 6 is a flow diagram of an embodiment of a method 80 for
making the energy storage component 14 that includes multiple
battery modules (e.g., the first battery module 30 and the second
battery module 28), in accordance with the present disclosure. In
the illustrated embodiment, the method 80 includes selecting the
first battery module 30 (block 82). The first battery module 30 may
be any type of energy storage unit, including, but not limited to,
a battery module (e.g., lead-acid battery module, lithium ion
battery module, or the like), a capacitor, an ultracapacitor, or
any combination thereof. As discussed above, the first battery
module 30 may include one or more battery cells 42. As a specific
example, the first battery module 30 may be a 12V lead-acid
battery.
[0058] The second battery module 28 may be connected with the first
battery module 30, both of which may be directly coupled to the
terminals 38, 40 of the energy storage component 14. The second
battery module 28 may include multiple battery cells 44. As
discussed above, the second battery module 28 may include more than
one chemistry, and the battery cells 44 of the second battery
module 28 may be selected, by varying both the number (e.g., the
total number of the battery cells 44, and the respective number of
the battery cells with each chemistry) and the chemistries of the
battery cells 44, to voltage match the first battery module (block
84). As discussed in detail above, the combination of the battery
cells 44, including the number and the chemistries, for the second
battery module 28 may be based on the overlap between the voltage
profile of the second battery module 28 and the voltage window 62
of the first battery module 30 (e.g., within a desired range of
SOC). In addition, the combination of the battery cells 44,
including the number and the chemistries, for the second battery
module 28 may be based on the overlap between the voltage profile
of the second battery module 28 and the operating window 70 of the
energy storage component 14 (e.g., within a desired range of SOC).
Once the battery cells 44 of the second battery module are
selected, these battery cells 44 may be assembled (e.g., in series,
in parallel, or a combination thereof) to form the second battery
module 28. The second battery module 28 and the first battery
module 30 may then be connected (e.g., in parallel) to form the
energy storage component 14 (block 86).
[0059] One or more of the disclosed embodiments, alone or on
combination, may provide one or more technical effects including
matching one battery module to another battery module in a batter
system. Combinations in both numbers and chemistries of battery
cells within the one battery module may be tuned for voltage
matching. Such tuning combinations of the battery cells may provide
increased design flexibility for battery modules. The technical
effects and technical problems in the specification are exemplary
and are not limiting. It should be noted that the embodiments
described in the specification may have other technical effects and
can solve other technical problems.
[0060] While only certain features and embodiments in accordance
with the present disclosure have been illustrated and described,
many modifications and changes may occur to those skilled in the
art (e.g., variations in sizes, dimensions, structures, shapes and
proportions of the various elements, values of parameters (e.g.,
temperatures, pressures, etc.), mounting arrangements, use of
materials, colors, orientations, etc.) without materially departing
from the novel teachings and advantages of the subject matter
recited in the claims. The order or sequence of any process or
method steps may be varied or re-sequenced according to alternative
embodiments. It is, therefore, to be understood that the appended
claims are intended to cover all such modifications and changes as
fall within the true spirit of the present disclosure. Furthermore,
in an effort to provide a concise description of the exemplary
embodiments, all features of an actual implementation may not have
been described (i.e., those unrelated to the presently contemplated
best mode of carrying out the disclosure, or those unrelated to
enabling the disclosure). It should be appreciated that in the
development of any such actual implementation, as in any
engineering or design project, numerous implementation specific
decisions may be made. Such a development effort might be complex
and time consuming, but would nevertheless be a routine undertaking
of design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure, without undue
experimentation.
* * * * *